Many researchers are studying the decision and executive functions of cortical areas and cortical networks and the plasticity of these networks. A major question about such cortical processing is how it is influenced by major subcortical systems interconnected with these cortical areas. For the basal ganglia, views have ranged from the basal ganglia serving mainly an automating function to the basal ganglia serving an instructive function, to the basal ganglia being involved both in selection and chunking functions leading to efficient release of behaviors in particular contexts. To approach this issue experimentally, we propose to record simultaneously the activity of neurons in cortex and striatum. We propose to compare and contrast anatomically-defined striosome-based and matrix-based corticostriatal circuits. To do this we will record in cortical areas of the anterior cingulate gyrus and prefrontal cortex, and at the same time record from projection neurons and interneurons in the anatomically defined corresponding corticorecipient zones of the striatum. Our goal is to identify activity patterns in these corresponding cortical and striatal zones in relation to action selection, reinforcement contingencies, decision variables, and automatization. To this end we have developed a joystick task and propose to record simultaneously from multiple sites in cortical areas and the striatum. We propose to analyze ensemble recording data, analyzing variations in responses over time during and between task trials. We have developed a step- by-step experimental strategy to do all ensemble recordings in relation to anatomically-defined corticostriatal and cortricocortical networks originating in cortical regions implicated in behavioral selection, and to identify networks differentially targeting striosomes and matrisomes in the striatum. The proposed work will contribute to a systematic, population-level analysis of cortico-basal ganglia activity related to action selection. This work has potential significance for studies of cortical and basal ganglia function and also for studies related to cortico-basal ganglia loop disorders including neurological disorders such as Parkinson's disease, Huntington's disease and neuropsychiatric disorders such as obsessive-compulsive disorders and Tourette's syndrome.